In the US, the Department of Defense and NASA are the two biggest consumers of aerospace technology and products.[citation needed] The Bureau of Labor Statistics of the United States reported that the aerospace industry employed 444,000 wage and salary jobs in 2004, many of which were in Washington and California,[citation needed] this marked a steep decline from the peak years during the Reagan Administration when total employment exceeded 1,000,000 aerospace industry workers.[9]

During that period of recovery a special program to restore U.S. competitiveness across all U.S. industries, Project Socrates, contributed to employment growth as the U.S. aerospace industry captured 72 percent of world aerospace market. By 1999 U.S. share of the world market fell to 52 percent.

Several consolidations took place in the aerospace and defense industries over the last few decades.

BAE Systems is the successor company to numerous British aircraft manufacturers which merged throughout the second half of the 20th century. Many of these mergers followed the 1957 Defence White Paper.

Airbus prominently illustrated the European airliner manufacturing consolidation in the late 1960s.[10]

On September 4, 2017, United Technologies acquired Rockwell Collins in cash and stock for $23 billion, $30 billion including Rockwell Collins' net debt, for $500+ million of synergies expected by year four.[16]

The Oct. 16, 2017 announcement of the CSeries partnership between Airbus and Bombardier Aerospace could trigger a daisy chain of reactions towards a new order.
Airbus gets a new, efficient model at the lower end of the narrowbody market which provides the bulk of airliner profits and can abandon the slow selling A319 while Bombardier benefits from the growth in this expanded market even if it holds a smaller residual stake.
Boeing could forge a similar alliance with either Embraer with its E-jet E2 or Mitsubishi Heavy Industries and its MRJ.[18]

On 21 December, Boeing and Embraer confirmed to be discussing a potential combination with a transaction subject to Brazilian government regulators, the companies’ boards and shareholders approvals.[19]
The weight of Airbus and Boeing could help E2 and CSeries sales but the 100-150 seats market seems slow.[20]
As the CSeries, renamed A220, and E-jet E2 are more capable than their predecessors, they moved closer to the lower end of the narrowbodies.
In 2018, the four Western airframers combined into two within nine months as Boeing acquired 80% of Embraer's airliners for $3.8 billion on July 5.[10]

On 26 November 2018, United Technologies announced the completion of its Rockwell Collins acquisition, renaming systems supplier UTC Aerospace Systems as Collins Aerospace, for $23 billion of sales in 2017 and 70,000 employees, and $39.0 billion of sales in 2017 combined with engine manufacturer Pratt & Whitney.[23]

In the 2000s Rolls-Royce reduced its supplier count after bringing in automotive supply chain executives.
On the Airbus A380, less than 100 major suppliers outsource 60% of its value, even 80% on the A350XWB.
Boeing embraced an aggressive Tier 1 model for the B787 but with its difficulties began to question why it was earning lower margins than its suppliers while it seemed to take all the risk, ensuing its 2011 Partnering for Success initiative, as Airbus initiated its own Scope+ initiative for the A320.
Tier 1 consolidation also affects engine manufacturers : GE Aviation acquired Avio in 2013 and Rolls-Royce plc is taking control of Industria de Turbo Propulsores.[24]

Hartley, Keith. The Political Economy Of Aerospace Industries: A Key Driver of Growth and International Competitiveness? (Edward Elgar, 2014); 288 pages; the industry in Britain, continental Europe, and the US with a case study of BAE Systems.

Newhouse, John. The Sporty Game: The High-Risk Competitive Business of Making and Selling Commercial Airliners. New York: Alfred A. Knopf, 1982. ISBN978-0-394-51447-5.